1. Field of the Invention
The present invention relates to an electronic device that can operate on a battery, such as a portable computer composed of a core unit (Core Unit) as the main body of a notebook PC (Personal Computer) and a docking unit (Dock Unit) for an extension, e.g., an ST docking unit (Standard Dock Unit) or a BJ docking unit (BJ Dock Unit), and a power source control method and device for controlling the power source of the electronic device.
2. Related Background Art
In a conventional portable computer (to be referred to as first prior art hereinafter) composed of a core unit (master unit) as the main body of a notebook PC and a BJ docking unit (docking unit) for an extension, low battery control remains the same regardless of whether the core unit operates alone or the core unit and the docking unit are connected (docked) to each other. Furthermore, the docking unit does not operate alone. That is, control for low voltages is performed according to one scheme.
In a conventional portable computer (to be referred to second prior art hereinafter) composed of a core unit (master unit) as the main body of a notebook PC and a docking unit for an extension, only a single docking unit is used, and optimization is achieved by charge/discharge control based on one scheme.
In a conventional portable computer (to be referred to third prior art hereinafter) composed of a core unit (master unit) as the main body of a notebook PC and a docking unit for an extension, the docking unit does not operate alone, and hence there is no need to select a power source to be started up in accordance with information indicating whether the docking unit is docked or not.
In a conventional portable computer (to be referred to fourth prior art hereinafter) composed of a core unit (master unit) as the main body of a notebook PC and a docking unit for an extension, power source control is performed only while the core unit operates alone and the core unit and the docking unit are docked to each other. However, since the docking unit does not operate alone, power source control is performed according to one scheme.
In a secondary battery charge scheme (to be referred to as fifth prior art hereinafter) in a control device that can operate on a secondary battery and has a charge circuit, charging is performed by using an AC adaptor or the like as a supply power source for the charge circuit. If the AC adaptor has sufficient power capacity, charging can be performed with full power while the control device normally operates. In general, however, the AC adaptor is manufactured in accordance with the maximum power of the control device owing to limitations on energy saving, cost, outer dimensions, and the like. For this reason, charging is not performed or performed with small power while the control device operates. When the power source of the control device is turned off, power from the AC adaptor can be fully used. In addition, in a control device in which two secondary batteries can be mounted, the two batteries are controlled independently in the same manner.
In the first prior art, when the BJ docking unit equipped with a xcexcBJ printer that becomes a large load variation element with respect to the battery-powered electronic device is connected to the core unit to build a system, the operation of the xcexcBJ printer must be inhibited before the system reaches its actual operation stop level as the battery residual capacity decreases in consideration of a drop in battery voltage due to a large load variation caused by the xcexcBJ printer. For this reason, the following problem is posed.
No consideration is given to control in a case in which the system does not reach its stop level as the battery residual capacity decreases after the xcexcBJ printer shifts to the operation inhibition level, and the current state must be canceled upon reception of power from a different power source such as an adaptor, and in a case in which the BJ docking unit is detached from the core unit to operate alone.
In the second prior art, no consideration is given to docking units having different power capacities, and no charge/discharge control is provided for the respective docking units. For this reason, the following problem is posed.
Since the system is optimized by one discharge/charge control scheme, when docking units having different power capacities are used, a discharge/charge control scheme that can be realized for the docking unit having the smaller power capacity is used. As a result, the docking unit having the larger power capacity cannot exhibit its power supply performance exceeding the performance defined in the control scheme.
In the third prior art, no consideration is given to a case in which the docking unit operates alone. That is, power source start-up control is not performed for the BJ docking unit alone. For this reason, the following problem is posed.
When a docking unit, such as the BJ docking unit, is to operate alone for replacement of the print head or the ink tank, a necessary power source cannot be selectively started up.
In the fourth prior art, although practical operations are limited, no power source control is performed for the BJ docking unit alone. For this reason, the following problem is posed.
Assume that the user forgets to turn off the power source while the BJ docking unit is operated alone to replace the print head or the ink tank. Such a situation cannot be properly handled because the main power source control unit is located on the core unit side.
In the fifth prior art, the secondary battery must be charged after the power source of the controller is turned off. If the power source is kept on, many hours are required to complete charging. For this reason, the following problem is posed.
As the controller is designed to be portable and driven on a secondary battery, its use is considerably limited.
The present invention has been made in consideration of the above problems in the prior art, and has as its first object to provide an electronic device which can perform processing control for a drop in battery voltage in accordance with the docking/non-docking state of a docking unit and a master unit.
It is the second object of the present invention to provide an electronic device obtained by docking a master unit and a docking unit to each other, which can perform optimal charge/discharge control for a secondary battery to be used.
It is the third object of the present invention to provide an electronic device which can perform control to selectively start up one of a plurality of electric circuits upon detection of the docking/non-docking state of a master unit and a docking unit.
It is the fourth object of the present invention to provide an electronic device which allows a power source control unit in a docking unit connected to a master unit to perform independent control upon detection of independent operation of the docking unit, e.g., turning off a power source upon detecting that a xe2x80x9cCAPACKxe2x80x9d state, in which no print command is issued to a printer, has continued for 15 min or more.
It is the fifth object of the present invention to provide a power source control method and device which can shorten the time required to charge a secondary battery with a simple circuit arrangement.
In order to achieve the first object, according to the present invention, there is provided an electronic device which can be driven on a battery and has a docking system configuration in which a docking unit mainly serving as an extension can be attached/detached to/from a master unit by using a system bus as a bridge, the docking unit operating alone upon start-up of a power source even while being detached from the master unit, and each of the docking unit and the master unit including docking detection means for detecting whether the units are docked to each other, residual capacity decrease detection means for detecting a decrease in residual capacity of a driving battery in steps, and execution means for selecting and executing operation suspending processing or operation end processing for the current system configuration when the residual capacity decrease detection means detects a decrease in residual capacity of the driving battery.
In order to achieve the second object, according to the present invention, there is provided an electronic device which can be driven on a battery and has a docking system configuration in which an extension portion can be detachably mounted by using a system bus as a bridge, the system comprising a plurality of extension portions, wherein a power source control IC of each of a master portion and the extension portions connected in the docking system includes setting means for selecting and setting a low battery detection threshold and a charge current limit which are unique to the current system.
In order to achieve the third object, according to the present invention, there is provided an electronic device having a docking system configuration in which a docking unit mainly serving as an extension can be attached/detached to/from a master unit by using a system bus as a bridge, the docking unit being capable of operating alone upon start-up of a power source even while being detached from the master unit, and the docking unit including docking detection means for detecting whether the docking unit is docked to the master unit, and control means for, when it is determined on the basis of the detection result obtained by the docking detection means that the docking unit operates as a docking system together with the master unit, performing power source control and initialization through the master unit, and for, when the docking unit operates while being detached from the master unit, controlling all power sources through a power source control unit in the docking unit.
In order to achieve the fourth object, according to the present invention, there is provided an electronic device which can be driven on a battery and has a docking system configuration in which a docking unit mainly serving as an extension can be attached/detached to/from a master unit by using a system bus as a bridge, the docking unit incorporating a printer and being capable of operating alone upon start-up of a power source even while being detached from the master unit, and each of the docking unit and the master unit comprising docking detection means for detecting whether the units are docked to each other, operation state detection means for detecting an operation state of the printer, and control means for, when the docking unit operates as a docking system together with the master unit, performing operation by power source control through the master unit, and for, when the docking unit operates while being detached from the master unit, controlling all power sources through a power control unit in the docking unit, and performing control to turn off the power source if no operation/print command is received after a lapse of a predetermined period of time.
In order to achieve the fifth object, according to the present invention, there is provided a power source control method comprising the detection step of detecting a current consumption of an electronic device that can be driven on a secondary battery, and the charge current control step of limiting a charge current in accordance with the current consumption detected in the detection step.
In addition, in order to achieve the fifth object, according to the present invention, there is provided a power source control method comprising the charge step of charging each of a plurality of secondary batteries of an electronic device that can be driven on the plurality of secondary batteries, and the charge control step of controlling charging of each second battery in the charge step.